Autologous fat transplantation alters gene expression patterns related to inflammation and hypoxia in the irradiated human breast

Adipose-derived Stem Cells and Wound Healing Are Progressively Impaired Long-term After Radiotherapy in Mice

Background

The pathogenesis of deterministic radiation damage is not clearly understood, but it has been reported that fibroinflammatory pathways are up-regulated. We hypothesized that the number of adipose-derived stem/stromal cells (ASCs) decline after radiotherapies, preventing normalization of fibrosis and angiogenesis, resulting in chronic radiation damages that progress over time.

Methods

Dorsal skin of 8-week-old male BALB/cfC3H mice was irradiated with 10 Gy weekly for 4 weeks. At 1, 3, 6, 9, and 12 months after radiotherapy (n = 5, 5, 5, 5, and 4), tissue hemoglobin oxygen saturation, and time until epithelialization were evaluated. Skin biopsies were measured for thickness and CD34+/isolectin- stem/stromal cell count. Nonirradiated (NRT) controls were evaluated at each time point as well (n = 5 each).

Results

Compared with NRT controls, time until epithelialization was significantly longer at 1 month (28 ± 3, P < 0.01); not statistically different at 3 months (16 ± 2, P = 0.32); and lengthened over time at 6 months (20 ± 2, P = 0.21), 9 months (28 ± 2, P < 0.01), and 12 months (26 ± 3, P < 0.01), as did tissue oxygen saturation. The number of CD34+/isolectin- ASCs decreased over time, at 1 month (5.3 ± 1.3, P = 0.01), 3 months (6.0 ± 1.4, P = 0.03), 6 months (4.0 ± 0.8, P < 0.01), 9 months (1.7 ± 0.5, P < 0.01), and 12 months (0.3 ± 0.5, P < 0.01). The subcutaneous fatty layer was significantly thinner at 3 months (116 ± 33, P < 0.01), 6 months (147 ± 22, P = 0.02), 9 months (52 ± 12, P = 0.04), and 12 months (89 ± 19, P = 0.04), but not at 1 month (141 ± 18, P = 0.43).

Conclusions

After 6 months postirradiation, the number of ASCs continued to decline over time, accompanied by irreversible progression of fibrosis, atrophy, and ischemia, which resulted in impaired wound healing.

Tissue-Level Effects of Autologous Fat Grafting in Hypertrophic Scars-A Case Series Study

INTRODUCTION

Fat grafting has antifibrotic effects and it improves scar quality. However, the biological mechanisms of fat grafts on scar healing are poorly understood.

METHODS

This was a prospective study to identify differences in the epidermal and dermal structure, macrophage infiltration, or inflammatory and fibrotic markers in hypertrophic scars before and after fat grafting surgery compared to normal skin. Seven patients with hypertrophic scar completed the study. Biopsies from hypertrophic scars and normal skin were taken at the time of fat grafting surgery and follow-up biopsies 6 mo postoperatively. A clinical Patient and Observer Scar Assessment Scale was used to monitor the clinical aspects of the scars. Immunohistochemical stainings were performed to analyze the changes occurring in the hypertrophic scar tissue after fat grafting.

RESULTS

Hypertrophic scars demonstrated decreased presence of rete ridges and increased levels of the profibrotic transforming growth factor beta-1 (TGF-β1) (P < 0.05) compared to normal skin. Fat grafting significantly increased the presence of rete ridges to the level of normal skin and reduced TGF-β1 expression (hypertrophic scars + fat) (P < 0.05). Fat grafting also increased the total macrophage count (CD68 pan-macrophage marker) (P < 0.05) and M1 macrophage count (inducible nitric oxide synthase M1 macrophage marker) (P < 0.05). The clinical evaluation of the scars (Patient and Observer Scar Assessment Scale) by the observer and patients improved after fat grafting (P < 0.05).

CONCLUSIONS

Our findings indicate that fat grafting promotes normalization of skin by improving epidermal structure and reducing TGF-β1 levels and favors less fibrotic healing by regulating macrophages levels.

Molecular biological mechanisms of radiotherapy-induced skin injury occurrence and treatment

Radiotherapy-Induced Skin Injury (RISI) is radiation damage to normal skin tissue that primarily occurs during tumor Radiotherapy and occupational exposure. The risk of RISI is high due to the fact that the skin is not only the first body organ that ionizing radiation comes into contact with, but it is also highly sensitive to it, especially the basal cell layer and capillaries. Typical clinical manifestations of RISI include erythema, dry desquamation, moist desquamation, and ulcers, which have been established to significantly impact patient care and cancer treatment. Notably, our current understanding of RISI's pathological mechanisms and signaling pathways is inadequate, and no standard treatments have been established. Radiation-induced oxidative stress, inflammatory responses, fibrosis, apoptosis, and cellular senescence are among the known mechanisms that interact and promote disease progression. Additionally, radiation can damage all cellular components and induce genetic and epigenetic changes, which play a crucial role in the occurrence and progression of skin injury. A deeper understanding of these mechanisms and pathways is crucial for exploring the potential therapeutic targets for RISI. Therefore, in this review, we summarize the key mechanisms and potential treatment methods for RISI, offering a reference for future research and development of treatment strategies.

Autologous fat transplantation prior to permanent expander implant breast reconstruction enhances the outcome after two years: a randomized controlled trial

Radiotherapy is important in breast cancer treatment. A side effect of the treatment is fibrosis that decreases the possibility for a successful breast reconstruction with expanders and with high patient satisfaction with the result. The most common option for mastectomized, irradiated women wishing for a breast reconstruction is autologous tissue transplantation. However, some patients are not suitable for flap surgery. Fifty mastectomized and irradiated women were included in a randomized controlled trial. They underwent breast reconstruction with expanders and were allocated 1:1 to either receive pre-treatment with autologous fat transplantation (AFT) or not. Primary outcomes were frequency of reoperations and complications. Secondary outcomes were number of days in hospital, number of outpatient visits to surgeon or nurse and patient reported outcome as reported with Breast Q. Follow-up time was 2 years. Fifty-two per cent of the intervention group and 68% of the controls underwent reoperations (p = 0.611). Thirty-two per cent of the intervention group and 52% of the controls had complications (p = 0.347). The median number of consultations with the nurse was four in the intervention group and six in the control group (p = 0.002). The AFT patients were significantly more satisfied with their breasts and psychosocial well-being after 2 years. They also had higher increase in satisfaction with breasts, psychosocial well-being, and sexual well-being when comparing baseline with 2 years postoperatively. This randomized controlled trial indicates benefits of AFT prior to breast reconstruction with expanders, especially on patient reported outcome even if the study sample is small.

Adipose-Derived Stromal Cell-Based Therapies for Radiation-Induced Fibrosis

Significance: Half of all cancer patients receive radiation therapy as a component of their treatment regimen, and the most common resulting complication is radiation-induced fibrosis (RIF) of the skin and soft tissue. This thickening of the dermis paired with decreased vascularity results in functional limitations and esthetic concerns and poses unique challenges when considering surgical exploration or reconstruction. Existing therapeutic options for RIF of the skin are limited both in scope and efficacy. Cell-based therapies have emerged as a promising means of utilizing regenerative cell populations to improve both functional and esthetic outcomes, and even as prophylaxis for RIF. Recent Advances: As one of the leading areas of cell-based therapy research, adipose-derived stromal cells (ADSCs) demonstrate significant therapeutic potential in the treatment of RIF. The introduction of the ADSC-augmented fat graft has shown clinical utility. Recent research dedicated to characterizing specific ADSC subpopulations points toward further granularity in understanding of the mechanisms driving the well-established clinical outcomes seen with fat grafting therapy. Critical Issues: Various animal models of RIF demonstrated improved clinical outcomes following treatment with cell-based therapies, but the cellular and molecular basis underlying these effects remains poorly understood. Future Directions: Recent literature has focused on improving the efficacy of cell-based therapies, most notably through (1) augmentation of fat grafts with platelet-rich plasma and (2) the modification of expressed RNA through epitranscriptomics. For the latter, new and promising gene targets continue to be identified which have the potential to reverse the effects of fibrosis by increasing angiogenesis, decreasing inflammation, and promoting adipogenesis.

Medium- and Long-Term Outcomes of Autologous Fat Grafting to Hands and Feet for Patients With Raynaud Phenomenon

BACKGROUND

Autologous fat grafting (AFG) has emerged as a promising treatment option for Raynaud phenomenon. However, existing studies are limited by short follow-up, and there is little evidence regarding predictive factors for successful outcomes.

METHODS

A retrospective chart review and standardized phone interviews were performed for all patients (n = 17, 65% response rate) treated with AFG to the hands or feet at our institution for primary or secondary Raynaud from 2010 to 2021. Each occurrence of AFG was defined as a separate surgery (n = 23), with an average follow-up of 3.7 years.

RESULTS

At follow-up, patients reported a 31% reduction in cold attack frequency, a 45% reduction in the intensity of individual attacks, a 29% reduction in the duration of attacks, and a 40% improvement in overall Raynaud Condition Score (P < 0.01). Although initial AFG to an extremity significantly improved symptoms, subsequent attempts were not shown to statistically improve outcomes. Digital ulcers were present in 65% of cases, and AFG resulted in ulcer healing in 87% of those cases. Median duration of maximum symptom relief was 1 year postoperatively, with 74% of patients reporting diminishing symptom relief by 4 years postoperatively. Those with a BMI ≥25, with primary Raynaud phenomenon or without preoperative ulcers experienced significantly longer symptom relief (P < 0.05). Average patient satisfaction was 7.7 of 10, and 91% would recommend the procedure to others.

CONCLUSIONS

Autologous fat grafting is an effective, albeit sometimes temporary, treatment for Raynaud and digital ulcers. Certain patients may be more likely to experience lasting symptom relief beyond 1 year.

Exploring the mechanisms behind autologous lipotransfer for radiation-induced fibrosis: A systematic review

AIM

Radiation-induced fibrosis is a recognised consequence of radiotherapy, especially after multiple and prolonged dosing regimens. There is no definitive treatment for late-stage radiation-induced fibrosis, although the use of autologous fat transfer has shown promise. However, the exact mechanisms by which this improves radiation-induced fibrosis remain poorly understood. We aim to explore existing literature on the effects of autologous fat transfer on both in-vitro and in-vivo radiation-induced fibrosis models, and to collate potential mechanisms of action.

METHOD

PubMed, Cochrane reviews and Scopus electronic databases from inception to May 2023 were searched. Our search strategy combined both free-text terms with Boolean operators, derived from synonyms of adipose tissue and radiation-induced fibrosis.

RESULTS

The search strategy produced 2909 articles. Of these, 90 underwent full-text review for eligibility, yielding 31 for final analysis. Nine conducted in-vitro experiments utilising a co-culture model, whilst 25 conducted in-vivo experiments. Interventions under autologous fat transfer included adipose-derived stem cells, stromal vascular function, whole fat and microfat. Notable findings include downregulation of fibroblast proliferation, collagen deposition, epithelial cell apoptosis, and proinflammatory processes. Autologous fat transfer suppressed hypoxia and pro-inflammatory interferon-γ signalling pathways, and tissue treated with adipose-derived stem cells stained strongly for anti-inflammatory M2 macrophages. Although largely proangiogenic initially, studies show varying effects on vascularisation. There is early evidence that adipose-derived stem cell subgroups may have different functional properties.

CONCLUSION

Autologous fat transfer functions through pro-angiogenic, anti-fibrotic, immunomodulatory, and extracellular matrix remodelling properties. By characterising these mechanisms, relevant drug targets can be identified and used to further improve clinical outcomes in radiation-induced fibrosis. Further research should focus on adipose-derived stem cell sub-populations and augmentation techniques such as cell-assisted lipotransfer.

Deconstructing Fat to Reverse Radiation Induced Soft Tissue Fibrosis

Adipose tissue is composed of a collection of cells with valuable structural and regenerative function. Taken as an autologous graft, these cells can be used to address soft tissue defects and irregularities, while also providing a reparative effect on the surrounding tissues. Adipose-derived stem or stromal cells are primarily responsible for this regenerative effect through direct differentiation into native cells and via secretion of numerous growth factors and cytokines that stimulate angiogenesis and disrupt pro-inflammatory pathways. Separating adipose tissue into its component parts, i.e., cells, scaffolds and proteins, has provided new regenerative therapies for skin and soft tissue pathology, including that resulting from radiation. Recent studies in both animal models and clinical trials have demonstrated the ability of autologous fat grafting to reverse radiation induced skin fibrosis. An improved understanding of the complex pathologic mechanism of RIF has allowed researchers to harness the specific function of the ASCs to engineer enriched fat graft constructs to improve the therapeutic effect of AFG.

Analysis of Fat Graft Survival and Platelet-Rich Plasma Effects: The Transcriptomic Differences

INTRODUCTION

Fat graft survival has been studied numerously but has not gone beyond hypothetical solutions. The molecular changes in survival of standard fat grafts and enhanced survival by platelet-rich plasma (PRP) are compared in this study to reveal the etiology that causes the loss of fat grafts after transplantation.

MATERIALS AND METHODS

A New Zealand rabbit's inguinal fat pads were excised and divided into three groups: Sham, Control (C), and PRP. Each weighing 1 g, C and PRP fat were placed into the bilateral parascapular area of the rabbit. After 30 days, the remaining fat grafts were harvested and weighed (C = 0.7 g, PRP = 0.9 g). All three specimens were put into transcriptome analysis. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes Analysis were done to compare the genetic pathways between the specimens.

RESULTS

Transcriptome analysis showed similar differential expressions in Sham vs. PRP and Sham vs. C comparisons, indicating the dominance of the cellular immune response in both C and PRP specimens. C and PRP comparison resulted in inhibited migration and inflammation pathways in PRP.

CONCLUSION

Fat graft survival is more related to immune responses than any other physiological process. PRP enhances survival by attenuating cellular immune reactions.

Capsular inflammation after immediate breast reconstruction - Gene expression patterns and inflammatory cell infiltration in irradiated and non-irradiated breasts

BACKGROUND

Capsular contracture following post-mastectomy radiotherapy (PMRT) is commonly seen in patients undergoing implant-based immediate breast reconstruction (IBR). Further understanding of the underlying biology is needed for the development of preventive or therapeutic strategies. Therefore, we conducted a comparative study of gene expression patterns in capsular tissue from breast cancer patients who had received versus those who had not received PMRT after implant-based IBR.

METHODS

Biopsies from irradiated and healthy non-irradiated capsular tissue were harvested during implant exchange following IBR. Biopsies from irradiated (n = 13) and non-irradiated (n = 12) capsules were compared using Affymetrix microarrays to identify the most differentially regulated genes. Further analysis using immunohistochemistry was performed in a subset of materials to compare the presence of T cells, B cells, and macrophages.

RESULTS

Enrichment testing using Gene Ontology (GO) analysis revealed that the 227 most differentially expressed genes were mainly involved in an inflammatory response. Twenty-one GO biological processes were identified [p < 0.05, false discovery rate (FDR) < 5%], several with B-cell-associated inflammation. Cell-type Identification by Estimating Relative Subsets of RNA Transcripts (CIBERSORT) analysis identified macrophages as the most common inflammatory cell type in both groups, further supported by immunostaining of CD68. Radiation remarkably increased B-cell infiltration in the capsular region of biopsies, as quantified by immunostaining of CD20 (p = 0.016).

CONCLUSIONS

Transcript analysis and immunohistochemistry revealed inflammatory responses in capsular biopsies regardless of radiotherapy. However, the radiation response specifically involved B-cell-associated inflammatory responses.

Effects of non-vascularized adipose tissue transplantation on its genetic profile

Subcutaneous adipose tissue (SAT) is recognized as a highly active metabolic and inflammatory tissue. Interestingly, adipose tissue transplantation is widely performed in plastic surgery via lipofilling, yet little is known about the gene alteration of adipocytes after transplantation. We performed an RNA-expression analysis of fat transplants before and after fat transplantation.In C57BL/6 N mice SAT was autologously transplanted. Samples of SAT were analysed before transplantation, 7, and 15 days after transplantation and gene expression profiles were measured.Analysis revealed that lipid metabolism-related genes were downregulated while inflammatory and extracellular matrix related genes were up-regulated 7 and 15 days after transplantation. When comparing gene expression profile 7 days after transplantation to 15 days after transplantation developmental pathways showed most changes.

Total breast reconstruction using large-volume condensed and viable fat grafting after mastectomy

Autologous fat grafting (AFG) has become a third alternative for breast reconstruction after mastectomy. However, total breast reconstruction using AFG remains a great challenge. We performed breast reconstruction using large-volume condensed and viable fat grafting in 30 postmastectomy patients (irradiated, n = 9; nonirradiated, n = 21). The grafts were purified and condensed by the washing and cotton gauze rolling technique. The surgical maneuver is designed to preserve the grafts viability. Three-dimensional expansion was applied where strong adhesions were present. Seven patients wore the Brava device for the expansion of the recipient site. The mean (SD) volume of fat grafted in each procedure was 230.5 (57.8) mL. The average number of sessions was 3.3 (0.7). The irradiated patients required more sessions than the nonirradiated patients (p=.017). The mean follow-up period was 12.8 (4.3) months. One patient (3%) developed postoperative cellulitis. Cysts and palpable nodules occurred in eight patients (27%) and one patient (3%), respectively. Severe dermatitis and skin pigmentation change occurred in one patient wearing the Brava device. The esthetic scores significantly improved after the treatments (p<.001). Approximately 90% of the patients were satisfied. No local recurrence or remote metastasis was documented during the follow-up period. Our study showed the success of total breast reconstruction using AFG. As a third alternative for breast reconstruction, total breast reconstruction using large volume condensed and viable fat grafting is an effective and safe approach for postmastectomy patients.

Molecular Profiling for Predictors of Radiosensitivity in Patients with Breast or Head-and-Neck Cancer

Nearly half of all cancers are treated with radiotherapy alone or in combination with other treatments, where damage to normal tissues is a limiting factor for the treatment. Radiotherapy-induced adverse health effects, mostly of importance for cancer patients with long-term survival, may appear during or long time after finishing radiotherapy and depend on the patient’s radiosensitivity. Currently, there is no assay available that can reliably predict the individual’s response to radiotherapy. We profiled two study sets from breast (n = 29) and head-and-neck cancer patients (n = 74) that included radiosensitive patients and matched radioresistant controls.. We studied 55 single nucleotide polymorphisms (SNPs) in 33 genes by DNA genotyping and 130 circulating proteins by affinity-based plasma proteomics. In both study sets, we discovered several plasma proteins with the predictive power to find radiosensitive patients (adjusted p < 0.05) and validated the two most predictive proteins (THPO and STIM1) by sandwich immunoassays. By integrating genotypic and proteomic data into an analysis model, it was found that the proteins CHIT1, PDGFB, PNKD, RP2, SERPINC1, SLC4A, STIM1, and THPO, as well as the VEGFA gene variant rs69947, predicted radiosensitivity of our breast cancer (AUC = 0.76) and head-and-neck cancer (AUC = 0.89) patients. In conclusion, circulating proteins and a SNP variant of VEGFA suggest that processes such as vascular growth capacity, immune response, DNA repair and oxidative stress/hypoxia may be involved in an individual’s risk of experiencing radiation-induced toxicity.

Radiation-Induced Skin Fibrosis: Pathogenesis, Current Treatment Options, and Emerging Therapeutics

Radiotherapy (RT) has become an indispensable part of oncologic treatment protocols for a range of malignancies. However, a serious adverse effect of RT is radiodermatitis; almost 95% of patients develop moderate to severe skin reactions following radiation treatment. In the acute setting, these can be erythema, desquamation, ulceration, and pain. Chronically, soft tissue atrophy, alopecia, and stiffness can be noted. Radiodermatitis can delay oncologic treatment protocols and significantly impair quality of life. There is currently a paucity of effective treatment options and prevention strategies for radiodermatitis. Importantly, recent preclinical and clinical studies have suggested that fat grafting may be of therapeutic benefit, reversing detrimental changes to soft tissue following RT. This review outlines the damaging effects of RT on the skin and soft tissue as well as discusses available treatment options for radiodermatitis. Emerging strategies to mitigate detrimental, chronic radiation-induced changes are also presented.